title: Reduced fat oxidation rates during submaximal exercise in adolescents with Crohn's disease.
abstract: BACKGROUND
  Children with Crohn's disease (CD) suffer from malnutrition. Understanding substrate utilization during exercise may help patients with CD sustain a healthy active lifestyle without compromising nutrition. The aim of this study was to determine whether substrate utilization and bioavailability during exercise are altered in children with CD compared with controls.
  
  
  METHODS
  Seven children with CD (mean age ± SD: 15.2 ± 2.3 yr) and 7 controls (14.4 ± 2.3 yr) were matched by sex and biological age. Participants completed 60 minutes of cycling at an intensity equivalent to 50% of their peak mechanical power. Rates of total fat and carbohydrate (CHO) oxidation, the amount of fat and CHO oxidized, and the contribution of fat and CHO to total energy expenditure were calculated from expired gases collected during exercise. Blood was collected before, during, and at the end of exercise and analyzed for insulin, free fatty acids, and glucose.
  
  
  RESULTS
  Whole-body fat oxidation rate (expressed in mg · kg(-1) of body weight per min) during exercise was lower in children with CD (5.8 ± 1.0) compared with controls (8.0 ± 2.2, P < 0.05). Children with CD relied significantly more on CHO, with approximately 10% greater contribution toward total energy expenditure (P < 0.05) than controls. There were no differences in plasma insulin, free fatty acids, or glucose between the groups.
  
  
  CONCLUSIONS
  Fat metabolism during exercise seems to be impaired in children with CD. A greater reliance on CHO is required to meet the energy demands of submaximal exercise.
authors.affiliation: *Child Health & Exercise Medicine Program, McMaster University, Hamilton, Ontario, Canada; †Department of Rehabilitation, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands; ‡McMaster Children's Hospital, Hamilton, Ontario, Canada; §Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada; and ‖University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Thanh
authors.initials: T
authors.lastname: Nguyen
authors.forename: Hilde E
authors.initials: HE
authors.lastname: Ploeger
authors.forename: Joyce
authors.initials: J
authors.lastname: Obeid
authors.forename: Robert M
authors.initials: RM
authors.lastname: Issenman
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Baker
authors.forename: Tim
authors.initials: T
authors.lastname: Takken
authors.forename: Gianni
authors.initials: G
authors.lastname: Parise
authors.forename: Brian W
authors.initials: BW
authors.lastname: Timmons
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D050260:Carbohydrate Metabolism; D016022:Case-Control Studies; D003424:Crohn Disease / Q000378:metabolism* / Q000473:pathology*; D015444:Exercise / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007328:Insulin / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D010084:Oxidation-Reduction; D011379:Prognosis
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin